The opportunity to personalize features in a mobile vehicle is ever increasing as the automobile is being transformed into a communications and entertainment platform as well as a transportation platform. Many new cars will be installed with some type of telematics unit to provide wireless communication and location-based services. These services may be accessed through interfaces such as voice-recognition computer applications, touch-screen computer displays, computer keyboards, or a series of buttons on the dashboard or console of a vehicle.
For example, a user can initiate a phone call from an in-vehicle mobile phone by announcing a call command. A call command can include the name or phone number of the person to be called. The telematics unit will repeat the phone number being called just before the call is initiated. The repeated phone number is generated by a speech-generation algorithm that provides audio signals for the string of numbers at a preset volume, without inflection and with a measured equal pause between each number. The acoustic waves generated by audio signal at a speaker have frequencies within the full range of frequencies heard by a human with average hearing.
In some cases, users may be prompted to enter information through a voice interface. The virtual utterances are synthetically generated at a preset volume, without inflection, with a measured equal pause between each word, and cover the full range of frequencies heard by a human with average hearing.
Typically, people say a phone number with a pattern of varying pauses between different numbers. For example, a person may say the number 555-222-3333 with short pauses between the fives (5's), a long pause between the final 5 and the first 2, short pauses between the twos (2's), a long pause between the last 2 and the first 3, and finally with short pauses between the threes (3's). This sequence of pauses and numbers can be illustrated as the following string in which each under-score represents a small pause and four under-scores in a sequence combine to form a long pause: 5—5—5— — — —2—2—2— — — —3—3—3—3. Some people have difficulty recognizing or remembering a number if the number is spoken in an unfamiliar pattern or if the pattern takes too long to announce.
If a person is in an MVCU with noisy background conditions, for example, if the window is open and trucks are passing at high speeds, then the person announcing a voice command to the telematics unit speaks loudly to ensure that the microphone in the vehicle picks up their voice command over the background noise. The telematics unit announces a virtual utterance responsive to the voice command, but the response may not be audible to the person in the vehicle because of the background noise.
Additionally, if the user of the telematics unit does not hear a portion of the frequency range that is normally heard by humans, then synthetically generated responses from the telematics unit can be difficult for the user to hear. For example, if a user is not able to hear acoustic waves at frequencies above a frequency, F1, and if forty percent (40%) of the acoustic waves produced by synthetically generated prompts in a telematics unit include frequencies above the frequency, F1, the ear of the user will only respond to sixty percent (60%) of the acoustic waves produced by synthetically generated prompt.
It is desirable to provide a method and system to synthetically generate prompts in a telematics unit, which mimic the pattern of a users speech. It is further desirable to provide a method and system to provide synthetically generated prompts in a telematics unit that match the volume level of the command that generated the prompt. It is further desirable to provide a method and system to synthetically generate prompts in a telematics unit that only produce acoustic waves having frequencies in the ranges of frequencies that are audible to the user of the telematics unit.